1. Field of the Invention
The present invention relates generally to a treadmill, and more particularly to a method of controlling the running status of a treadmill.
2. Description of the Related Art
A conventional electrical treadmill has a motor to drive a belt, on which user can run. User also can adjust the speed of the belt by controlling the motor, such that user can choose a suitable condition to exercise on the treadmill.
For the safety of user, the conventional electrical treadmill is provided with a safety apparatus to detect the speed of motor. While the speed of the motor is lower to a predetermined value, which indicate that the belt may be jammed, the safety apparatus will stop the motor automatically for safety of user.
In case of a heavier user running on the belt of the treadmill in a lower running speed, and at the moment of the user stepping on the belt, the speed of the motor is lowered because of the suddenly greater loading. At this condition, the safety apparatus may be false alarm and stop the motor immediately to stop the exercise.
A feedback control system is provided to overcome the drawback described above.
The feedback control system has a sensor to detect the voltage and current of the motor and to control the speed of motor according to the voltage and current. For a example, in the case of a heavier user running on the belt of he/she running faster that increase the loading of the motor, the sensor will detect that and increases the voltage and current supplying to the motor to increase the speed or torque of the motor that would approach the speed of the belt to the actual condition. For an opposite condition, the safety apparatus decreased the voltage and current supplying to the motor to lower the speed or torque of the motor.
If the belt is jammed by extremities, a shoelace or clothes of user that increase the loading of the motor, the safety apparatus increases the voltage and current supplying to the motor after it detect that condition that would make the user in trouble to get out, and he/she might fell down and get injure in this condition. If the user get off the treadmill, the safety apparatus only detects the loading of the motor is lower and decreases the voltage and current supplying to the motor. In this condition, the belt keeps running but nobody on it. If the treadmill has not been turned off, and a child steps on it, the child would get injure.
In addition, if the treadmill is shown in an exhibition, and no one stands on the belt, the safety apparatus will restrict the belt running in a lower speed that might mistake the consumes that the treadmill only can run in a lower speed.